عَنْ ابْنِ عَبَّاسٍ رَضِيَ اللَّهُ عَنْهُمَا قَالَ آخِرُ شِدَّةٍ يَلْقَاهَا الْمُؤْمِنُ الْمَوْتُ وَفِي قَوْلِهِ {يَوْمَ تَكُونُ السَّمَاءُ كَالْمُهْلِ} [المعارج: 8] قَالَ كَدُرْدِيِّ الزَّيْتِ وَفِي قَوْلِهِ {آنَاءَ اللَّيْلِ} [آل عمران: 113] قَالَ جَوْفُ اللَّيْلِ وَقَالَ هَلْ تَدْرُونَ مَا ذَهَابُ الْعِلْمِ قَالَ هُوَ ذَهَابُ الْعُلَمَاءِ مِنَ الْأَرْضِ
It is narrated from Sayyiduna Abdullah bin Abbas, may Allah be pleased with them both, that the last hardship a believer faces among the hardships of the world is the hardship of death. Allah the Exalted says: {یَوْمَ تَکُونُ السَّمَاءُ کَالْمُہْلِ} … On the day when the sky will become like the dregs of oil. That is, it will become like the sediment that settles at the bottom of oil, and {آنَائَ اللَّیْلِ} refers to the innermost part of the night. Also, Sayyiduna Ibn Abbas, may Allah be pleased with them both, asked: Do you know how knowledge will be taken away? Its form will be that the scholars will be taken away from the earth.